Electrical heating unit.



F. W. BALL.

ELECTRICAL HEATING UNIT.

APPLICATION FILED AUG. 26, 1914.

1,119,336, Patented De0.1,1914

UNITED STATES PATENT OFFICE.

FRANK WYLDE BALL, 0F MELBOURNE, VICTORIA, AUSTRALIA.

ELECTRICAL HEATING UNIT.

Specification of Letters Patent.

Patented Dec. 1', 1914.-

Application filed August 26, 1914. Serial No. 858,684.

This invention relates to an improved accompanying sheet of explanatory drawings, where1n:

Figure 1 is a view in side elevation of an electrical heating unit constructed according to the present invention. Fig. 2 is a longitudinal sectional elevation of Fig. 1, omitting the high resistance wire. Figs. 3, at and 5 are views partly in section and partly-in elevation of modified forms of the invention and hereinafter are fully described.

In these drawings like characters of reference have been employed to indicate similar or corresponding parts in the difl erent views and the letter a designates a tube of pure quartz which is mounted on a metallic rod 7) of suitable diameter and shape. The hole in the quartz tube a is made to correspond tothe shape of the rod 6 and the said tube is arranged to slide freely over the said rod. The quartz tube a is retained in its correct position on the rod 79 by nuts 0 keys, pins or the-like and its periphery is provided with. a helically cut groove d of preferred shape to take a high resistance wire or ribbon e. The high resistance wire or ribbon e is wound in the helically formed groove (Z and i one of its ends is secured to an end of the lead and return wires respectively disposed in the most approved way to suit the construction of article or utensil to which the invention is fitted. One or more windings or layers of mica g or other non-conducting material is interposed between the rod 7) and the quartz tube a; so as to further increase the insulating effect.

In lieu of employing a solid metal rod 17 for a return lead through the quartz tube a a tubular rod 72 can be used and water or other liquid can be passed therethrough to be heated for any purpose desired.

The quartz tube a can be made of any convenient length and if preferred two or more lengths placed end to end on the rod 6 can be employed to form each heating unit.

2' indicates a tubular covering which is preferably of quartz and is placed over the quartz tube a while a layer of mica 9' or other suitable non-conducting material can be interposed between this covering and the tube a.

The tubular covering '5 is retained in position on the quartz tube a by a flange k on the ferrule f and a washer Z on the opposite end of the rod 6. The ferrule f is retained fixedly in position on the quartz tube a in an approved manner as by pressing a tongue m, formed on the former, into a recess 92 formed in the latter.

A.modification of the invention is shown in Fig. 4- ofthe drawings and consists in arranging a plurality of interfitting tubes 0 over the tube a. These tubes 0 are provided with helical grooves on their peripheries to accommodate a high resistance wire 6.

In winding a unit of this construction the wire e is wound in the groove in the tube a and then the firsttube 0 is slid thereover after which the wire is wound in the opposecond tube 0 is slid thereover and the wire I is then wound in the groove formed in its periphery.

If preferred an outer tube'z' of -quartz can be employed to cover the groove in the outer tube and the wire wound therein, and a layer of nicaj or other suitable non-conducting material can be interposed between the tube 0 and covering 2'. The tubes 0 are retained in their correct positions by a flange on the ferrule f and a washer Z on the opposite end of the rod 6. One end of the wire e is passed through a hole in the flange on and secured to the ferrule f and the other end is secured to the end of the rod 6 located at the opposite end of the unit.

The said tube a is made by bringing powdered or crushed quartz to a molten state and thencasting or molding it to the shape required.

. The helical groove 03 in the quartz tube a is out with acarborundum stone revolved -'at high speed and passing backward and' comprising a supporting rod, a plurality of interfitting tubes of quartz fitting over said rod, said tubes having formed on the peripheries thereof helical grooves, a high resistance wire wound in the grooves of said tubes and having its end connected to said rod and to a terminal on one end of the inner tube, and layers of non-conducting material arranged around said supporting rod and around the grooved peripheries of. the interfitting tubes, substantially as described.

2. An improved electrical heating unit comprising a supporting rod, a plurality of interfitting tubes of quartz fitting over' said rod, said tubes having formed on the peripheries thereof helical grooves, a high resistance wire wound in the-grooves of said tube, and a tubular covering of quartz and rod and to a terminal at one end of the inner tube, and a tubular covering of. quartz and a layer of'mica or non-conducting material interposed between said tubular covering and the outer tube, substantially as described.

In witness whereof I have signed this specification in the-presence of two Witnesses.

FRANK WYLDE BALL.

Witnesses:

G. MONAMARA, WILLIAM A. ASHTON. 

